Electrical package for lsi devices and assembly process therefor

Abstract

An electrical package for Large Scale Integrated (LSI) devices includes a carrier having (a) thermal expansion similar to a semiconductor, (b) a standard array of terminal pins (100 or more) and (c) a circuit transposer that is (i) a semiconductor material, typically silicon and (ii) readily personalized to connect any combination of attached LSI devices to the input-output terminal pins. The package utilizes solder technology to interconnect the carrier, circuit transposer and LSI devices. The carrier and semiconductor transposer eliminate mechanical stress on the solder joints that would otherwise occur from thermal coefficient expansion (TCE) mismatch between dissimilar package materials. The circuit transposer increases the wirability of electrical packages utilizing solder technology. Reliability problems presented by thick film paste or metallized conductors on carriers are also overcome by the semiconductor circuit transposer. The package may be fabricated by commercially acceptable processes that are automatable.

What is claimed is: 
     
       1. An electrical package for large scale integrated devices comprising a. a carrier having terminal members supported therein having circuits thereon,   b. a circuit transposer attached to the carrier terminal members with at least one semiconductor active element mounted on the transposer, the transposer being of the same material as the active element,   c. the carrier being a plastic substrate, having a greater coefficient of thermal expansion than the active element, and uniformally encapsulating an imbedded metallic web having a coefficient of thermal expansion lower than the active element to make the overall coefficient of expansion of the carrier equal to the active element,   d. the coefficient of thermal expansion of the carrier, transposer and semiconductor active element being 3:3:3 when at operating temperature.